Except where noted otherwise, data are given for materials in their standard state (at 25C, 100kPa)
Infobox references
Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is a chemical compound with the formula [NH4]2[PtCl6]. It is a rare example of a soluble platinum(IV) salt that is not hygroscopic. It forms intensely yellow solutions in water. In the presence of 1M NH4Cl, its solubility is only 0.0028 g /100 mL.
Preparation and structure
The compound consists of separate ammonium cations and octahedral [PtCl6]2 anions. It is usually generated as a fine yellow precipitate by treating a solution of hexachloroplatinic acid with a solution of an ammonium salt. The complex is so poorly soluble that this step is employed in the isolation of platinum from ores and recycled residues.
Uses and reactions
Ammonium hexachloroplatinate is used in platinum plating.
Heating [NH4]2[PtCl6] under a stream of hydrogen at 200 C produces platinum sponge. Treating this with chlorine gives H2PtCl6. Platinum salts are sensitizing agents and should only be handled by experts due to the very small exposure limit which may cause platinosis.
References
^ a b George B. Kauffman (1967). "Ammonium Hexachloroplatinate(IV)". Inorganic Syntheses 9: 182185. doi:10.1002/9780470132401.ch51.
^ Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN 0-7514-0413-6.
